How fast will your physical abilities decline as you age? New statistical research from Yale University shows that you actually might not slow down as much or as quickly as you'd think.

Two researchers from Yale University analyzed how rapidly runners can expect to slow down as they age. They gathered data from world records on running events from 5Ks and full marathons to road races and trail runs, and they found that runners generally maintain a slow rate of decline until age 80. Even 90-year-olds can expect to be only twice as slow as they were in their prime—which is pretty good for age 90! The best news is that, according to the research, age-related physical decline isn't likely to start until age 40 at the earliest.

The Yale researchers also created a calculator based on their new data to give people a tailored look into their possible athletic futures. This calculator is available for free online: To find estimates about how much you might slow down over the years, click on "All other running (2018 updated age factors)" and enter your best time for whatever event interests you most. (If you're under age 40, you should still enter 40 as the age; the model doesn't go down lower than that.)

For example, my best half marathon time is 2 hours and 3 minutes. I entered that time into the calculator with age 40 (even though I'm 28), and it showed me some exciting predictions: At age 55, I should still be able to run a half marathon in 2 hours and 22 minutes. When I turn 80, if I'm still running half marathons (which I highly doubt, but hey—who knows!), I'll be able to run those 13.1 miles in 3 hours and 4 minutes. Not too shabby!

Of course, this model is based on information from mostly world-class runners. Recreational runners may slow a little more quickly than the statistics show on the calculator, the researchers told the New York Times. Women were also not included in the study at all due to a lack of historical data on older female runners.

Still, the predictions give us all something to shoot for. Knowing that our bodies have the potential to remain in pretty excellent shape throughout our oldest years should inspire us to keep up our movement routines as we get older. After all, exercise itself has been proven to slow and even reverse the effects of aging on our bodies. If being able to be physically fit when you're older is important to you (and it should be!), that body-strengthening work starts today.